azure-communication-common_1.0.1

Fix issue in APIView feedback (#796)

* Fix issue in APIView feedback
* Remove credential policy
* Make ChatError & AddChatParticipantsResult Immutable, add retryPolicy for builder
* Update addEventHandler to return listener id
* Add @throw annotations, make communicationTokenCredential mandatory in builder, put authorizationPolicy after retryPolicy in builder
* Fix unit test with mock android.util.Base64
* Add copyright
* fix comment & README.md
* Update mock class license
* Update signaling client initialization process
* Update ChatEvent getThreadId to getChatThreadId
* Update addEventHandler behavior
* Update release date